2026 Rankings

ZIP Codes with Most EPA Violations in California — 2026

Last updated: August 31, 2026

622 ZIP codes ranked by Recorded EPA Violations #1: ZIP 92880 (Corona, CA) - 46
Lead Violations Lowest Score Safest Flood Risk Energy Cost Radon PFAS Reliability EJ Index Homebuyer Risk CO & Gas Safest Gas Remediation Burden Unresolved Violations (by Utility) Water Equity (by Utility)

Out of 622 ZIP codes with data in California, these are the highest-ranked areas for recorded epa violations. See also: National ZIP Codes with Most EPA Water Violations | All California Rankings

Statistic Value
ZIP codes ranked 622
Highest value 46
Median value 2
State California

Top 100 Worst ZIP Codes

Rank ZIP Code City State Recorded EPA Violations Safety Score
1 92880 Corona CA 46 60/100
2 93455 Santa Maria CA 46 43/100
3 92503 Riverside CA 45 60/100
4 92860 Norco CA 45 44/100
5 92256 Morongo Valley CA 43 —
6 92059 Pala CA 42 70/100
7 92061 Pauma Valley CA 42 87/100
8 92082 Valley Center CA 42 70/100
9 93257 Porterville CA 41 54/100
10 93247 Lindsay CA 39 56/100
11 93420 Arroyo Grande CA 37 62/100
12 93445 Oceano CA 37 78/100
13 93307 Bakersfield CA 29 42/100
14 93534 Lancaster CA 29 70/100
15 93907 Salinas CA 28 69/100
16 90660 Pico Rivera CA 26 50/100
17 93536 Lancaster CA 25 72/100
18 93560 Rosamond CA 25 72/100
19 90606 Whittier CA 24 50/100
20 91768 Pomona CA 24 54/100
21 92065 Ramona CA 23 82/100
22 95020 Gilroy CA 23 —
23 95033 Los Gatos CA 23 53/100
24 95037 Morgan Hill CA 23 —
25 95326 Hughson CA 23 84/100
26 92284 Yucca Valley CA 22 74/100
27 92223 Beaumont CA 20 65/100
28 92407 San Bernardino CA 20 65/100
29 92320 Calimesa CA 19 49/100
30 92220 Banning CA 18 67/100
31 93245 Lemoore CA 18 89/100
32 95006 Boulder Creek CA 18 68/100
33 95060 Santa Cruz CA 18 68/100
34 93243 Lebec CA 17 72/100
35 93614 Coarsegold CA 17 52/100
36 92411 San Bernardino CA 16 70/100
37 92561 Mountain Center CA 15 —
38 95315 Delhi CA 15 —
39 95380 Turlock CA 15 90/100
40 92356 Lucerne Valley CA 14 —
41 93314 Bakersfield CA 14 58/100
42 93454 Santa Maria CA 14 58/100
43 94533 Fairfield CA 14 85/100
44 94585 Suisun City CA 14 85/100
45 95066 Scotts Valley CA 14 67/100
46 95324 Hilmar CA 14 100/100
47 96150 South Lake Tahoe CA 14 61/100
48 93060 Santa Paula CA 13 59/100
49 93274 Tulare CA 13 58/100
50 93444 Nipomo CA 13 83/100
51 93620 Dos Palos CA 13 99/100
52 93665 South Dos Palos CA 13 99/100
53 95370 Sonora CA 13 76/100
54 95383 Twain Harte CA 13 70/100
55 90640 Montebello CA 12 51/100
56 91732 El Monte CA 12 42/100
57 92308 Apple Valley CA 12 62/100
58 93225 Frazier Park CA 12 74/100
59 93446 Paso Robles CA 12 59/100
60 95017 Davenport CA 12 —
61 95346 Mi Wuk Village CA 12 —
62 93312 Bakersfield CA 11 58/100
63 93561 Tehachapi CA 11 47/100
64 95333 Le Grand CA 11 —
65 95404 Santa Rosa CA 11 89/100
66 92236 Coachella CA 10 70/100
67 93001 Ventura CA 10 61/100
68 93012 Camarillo CA 10 43/100
69 93023 Ojai CA 10 59/100
70 93292 Visalia CA 10 46/100
71 93426 Bradley CA 10 —
72 93451 San Miguel CA 10 —
73 95073 Soquel CA 10 77/100
74 95305 Big Oak Flat CA 10 56/100
75 95388 Winton CA 10 87/100
76 91770 Rosemead CA 9 72/100
77 92539 Anza CA 9 —
78 93036 Oxnard CA 9 56/100
79 93203 Arvin CA 9 68/100
80 93308 Bakersfield CA 9 48/100
81 93553 Pearblossom CA 9 —
82 94574 Saint Helena CA 9 —
83 95311 Coulterville CA 9 —
84 95476 Sonoma CA 9 69/100
85 95685 Sutter Creek CA 9 76/100
86 96007 Anderson CA 9 89/100
87 92544 Hemet CA 8 72/100
88 92549 Idyllwild CA 8 —
89 93230 Hanford CA 8 86/100
90 93250 Mc Farland CA 8 69/100
91 93551 Palmdale CA 8 72/100
92 95018 Felton CA 8 71/100
93 95023 Hollister CA 8 60/100
94 95041 Mount Hermon CA 8 —
95 95327 Jamestown CA 8 77/100
96 90755 Signal Hill CA 7 71/100
97 90806 Long Beach CA 7 71/100
98 91006 Arcadia CA 7 53/100
99 92251 Imperial CA 7 83/100
100 92305 Angelus Oaks CA 7 —

Methodology

Violation counts include all types recorded in the EPA SDWIS database: Maximum Contaminant Level (MCL) violations, treatment technique violations, and monitoring/reporting violations. Both resolved and unresolved violations are counted. Higher counts may reflect longer system histories or larger service areas.

Data sources: EPA Safe Drinking Water Information System (SDWIS), FEMA National Flood Insurance Program, EPA radon zone maps, EIA electricity rates, and Consumer Confidence Reports. Last updated: 2026-08-31.

Frequently Asked Questions

What counts as an EPA water violation?

EPA violations include exceeding Maximum Contaminant Levels (MCLs), failing to treat water properly (treatment technique violations), and not testing or reporting on schedule (monitoring violations). Health-based violations are the most serious.

Does a high violation count mean the water is unsafe now?

Not necessarily. Many violations are historical or monitoring-related. However, a pattern of repeated violations indicates systemic issues with water system management or infrastructure.

Explore More Rankings

How this ranking is calculated, data sources, and limitations: Rankings Methodology →

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Disclaimer: Rankings are based on EPA, FEMA, and federal agency data. They reflect historical patterns and risk indicators, not necessarily current conditions. For the most current information, contact your local water utility or request a Consumer Confidence Report.

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